Grinding machine



Sept. 16, 1924.

-A. M. DRAKE GRINDING MACHINE Filed Dec. 21, 1922 the usual head, inwhich is journalled' a ro-- Patented Sept. 16, 1924.,

1? TATE ALDEN M. DRAKE, OF WORCESTER, MASSACH USETTS, ASSIGNOR TO THEHEALD' MACHINE COMPANY, OF WORCESTER, .MA SSACHUSETTS, A CORPORATION -OFMASSACHUSETTS.

GRINDING MACHINE.

"Application filed. December 21, 1922. Serial No.608,182.

To all whom it may concern:

Be it known that I, ALDEN M. DRAKE,

a citizen of the United States, residing at Worcester, in the county ofWorcester and Commonwealth of Massachusetts, have invented a new anduseful Improvement in a Grinding -Machine, of which the following,together with the accompanying drawings, is a specification.

The present invention relates to grinding machines. The inventioncontemplatesan improved belt drive between an overhead line shaft andthe grinding wheel spindle, so arranged as to insure adequate belt wrapon said spindle, and the maintenance of proper tension in the severalbelts,lin all positions of operation of said wheel. The

above and other advantageous features of my invention .will hereinaftermore fully appear, reference being had to the accompanying drawings, inwhich-.

Fig. 1 is a view in rear elevation, showing a grinding machine embodyingmy invention.

Fig.2 is an end view, partially in section, of the machine shown in Fig.1.

Like reference characters refer to like parts in the different figures.

For purposes of illustration, the invention is shown herewith as appliedto an in ternal grinder, the base 1 of which carries tatable workspindle 2. The spindle 2 serves for the support and rotation of the workand is adapted to be driven at a moderate speed by means of a pulley 3,on in any other suitable manner.- Thebase 1 is provided withlongitudinal ways 4, a, for slid'ably supporting a table 5 which carriesa rotating grinding wheel 6. Longitudinal movement of the table on thebase causes the wheel 6 to traverse the rotating work, thus procuring ina manner well known in the art, a uniform grinding action over theentire interior surface of therecess or hole'in the work.

The grinding wheel 6 is hereshown as mounted on the end of a spindle 7,which moves with the table 5 and is provided with a pulley 8, wherebythe spindle 7 may be driven at high speed by means of a belt 9. The belt9 connects the pulley 8 to a pulley 10 on a countershaft 11, upon whichis mounted a second pulley 12 carrying a belt 18 passing upwardly to theusual elongated 'drum, not shown, on an overhead line shaft.

In the particular machine heroin illustrated, provision is made for across feed of the grinding wheel 6 in a direction transverse to the,lineof movement of the table 5, and to this end the wheel spindle 7,

together with its driving devices adjacent thereto, is supported u on across slide 14,

.the latter being mo-va le transversely on suitable ways 15 provided onthe table 5, as by means of hand-wheel 14'.

To the cross slide 14 is adjustably secured a bracket member 16, havingan upwardly 'extending portion 17 overhan ing the base 1 and table Thecounters raft 11, carrying the pulleys 10 and 12 is journalled in an arm18, which is pivotally mounted on the portion 17 of the bracket 16 wmeans of a pin 19. The arm 18 is provided with a lug 20 having openings21 for receiving a chain 22. The chain 22 is retained in one of theopenings 21 by means of a set screw23, the end of which is ada ted toengage one of the links of the c ain 22. The chain 22 passes downwardlyfrom the lug 2O overa pulley 2/1 carried by the bracket 16, and its endis attached to a spring 25. The other end of the spring 25 is connectedto the cross slide 14 by means of a pin 26, so that thespring 25tends-to exert a downward pull on the arm 18'carrying the countershaft11.,

The belt 9 in engagedby an idle or tight-. ener pulley 27, carried atthe end of an arm 28, the latter being pivotally mounted on a pin 29which is carried by the-bracket 16. As shown in Fig. 2, the pivot pin 29is surrounded by a coil spring 30, one end of which is secured to thebracket 16 by a stud 31, and the other end of which is seated in one ofthe several 'holes 28 provided in the arm 28 and tends to turn it in aclock Wise direction about its pivotpin 29, so that the pulley 27 isadapted at all times to take up any looseness in the belt 9, and also toinsure the adequate wrap of said belt around the wheel spindle pulley 8.

From a consideration of the foregoing, it is apparent that by myinvention I have provided an improved arrangement whereby both of thebelts which transmit power from the line shaft to the wheel spindle 7areat all times maintainedat the proper tension, the one independently ofthe other. The belt 13 is always held taut by the action of the spring25 which tends to pull the arm 18 downward. At the same time, the pulley27 eliminates any slack in the belt 9 by the action of the spring 30tending to throw the arm 28 in a clockwise direction. The belts 9 and 18willalso always be held at the proper tension irrespective of theshifting of the cross slide 14, as the grinding wheel 6 is fedtransversely with respect to thework. It therefore follows that agrinding maching embodying my invention will always operate in a uniformmanner, owing to they fact thatthe speed of the tool spindle 7 remainsconstant and is not subject to fluctuations, due to changes in the belttension as the cross slide 14 is shifted during the operation of themachine.

exerted by the springs and 30, rcspecr,

The exact amount of tension of the belts 9 and '13 may be closelyregulated by the means provided for adjusting the forces tively. Theeffective length of the chain 22 is determined by the particular linkwhich is engaged by the pin 21, so that the pressure exerted by thespring25 on themay be adjusted by causing the end of the spring 30 toengage in different holes 28 provided on the arm 28. By the adjustmentsabove described, a proper balance can be obtained between the forcesexerted on the countershaft 11 and the idler pulley 27 which will bemaintained throughout the operation of the machine, as previously setforth. The bracket 16 can be moved bodily on the cross slide 14 byreason of its connection thereto by a foot 82 received in a slot 33,whereby the belting can be adjusted when set-ting up the machine, in 'advance of ,the more delicate adjustments of the spring-s25 and 30.

I claim,

In a grinding machine, a base, a table longitudinally movable thereon, agrinding wheel spindle carried by said table and adjustable crosswisethereof, and means for driving said spindle from an overhead line shaft,said driving means comprising a belt driven counter-shaft which isbelted itself to said spindle, incombination with a spring drawingdownwardly on said countershaft,

and abelt tightener acting on said spindle belt, the latter providing awrap around the spindle pulley in all positions of cross wise adjustmentof said spindle.

Dated this 15th day of December; 1922.

ALDEN M. DRAKE.

